1. Field of the Invention
The present invention relates to information processing apparatuses, information processing methods, and programs. More particularly, the present invention relates to an information processing apparatus, an information processing method, and a program, which are capable of rapidly displaying a three-dimensional map with higher reality.
2. Description of the Related Art
For example, vehicle navigation systems render all rendering objects, such as buildings and interchanges, which are located within a predetermined geographical range with respect to a focal point, for example, the current position, to generate and display a three-dimensional map, which is a map composed of a three-dimensional image.
However, when the vehicle navigation systems render all the many rendering objects within a predetermined geographical range, the amount of rendering processing is increased and it takes much time to display the three-dimensional map.
In order to resolve the above problem, a method of varying the detail level of rendering in accordance with the distance from the focal point to generate a three-dimensional map is proposed (for example, refer to Japanese Unexamined Patent Application Publication No. 2005-56075). In this method, the detail level of rendering is decreased with the increasing distance from the focal point to the rendering object and the rendering objects, the distances to which from the focal point are longer than a predetermined distance, are not rendered.
Vehicle navigation systems that render only the rendering objects close to the focal point without varying the detail level and that do not render the rendering objects far from the focal point are also proposed.
FIGS. 1 to 4 illustrate such a vehicle navigation system in related art.
FIG. 1 is a block diagram showing an example of the configuration of the vehicle navigation system in the related art.
The vehicle navigation system includes a global positioning system (GPS) satellite 11 and a vehicle navigation apparatus 21. The vehicle navigation apparatus 21 includes a focal point acquiring unit 22, an azimuth acquiring unit 23, a rendering area calculating unit 24, a three-dimensional map data database (DB) 25, a three-dimensional map data retrieving unit 26, a three-dimensional rendering data DB 27, a three-dimensional rendering data reading unit 28, and a display unit 29. The vehicle navigation apparatus 21 is mounted in a vehicle, such as a car.
The GPS satellite 11 transmits a signal wave to the vehicle navigation apparatus 21.
The focal point acquiring unit 22 receives the signal wave transmitted from the GPS satellite 11, calculates the current position of the vehicle by a predetermined calculating method, and supplies the calculated current position as a focal point, which is a reference point used for defining a rendering area in which a three-dimensional map is generated, to the rendering area calculating unit 24. The focal point acquiring unit 22 acquires the focal point, for example, periodically or when the vehicle reaches an intersection. The focal point acquiring unit 22 may acquire a position on the map, specified by a user with an operation unit (not shown), such as a tablet, as the focal point.
The azimuth acquiring unit 23 uses, for example, a geomagnetic sensor or a gyroscope identifying the azimuth of the vehicle to detect (calculate) the azimuth of the vehicle and supplies the detected azimuth to the rendering area calculating unit 24. The azimuth acquiring unit 23 may acquire an azimuth from data indicating the azimuth, input by the user with the operation unit (not shown), such as the tablet.
The rendering area calculating unit 24 calculates a rendering area in which a three-dimensional map is generated on the basis of the focal point supplied from the focal point acquiring unit 22 and the azimuth supplied from the azimuth acquiring unit 23 and supplies the calculated rendering area to the three-dimensional map data retrieving unit 26.
The three-dimensional map data DB 25 has three-dimensional map data concerning the map recorded therein. The three-dimensional map data is used for generating a three-dimensional map. The three-dimensional map data includes rendering object data concerning the rendering objects, such as buildings, located in the rendering area, which is a geographical range.
The three-dimensional map data retrieving unit 26 retrieves, from the three-dimensional map data DB 25, the rendering object data within a predetermined range in the rendering area supplied from the rendering area calculating unit 24 and supplies the retrieved rendering object data to the three-dimensional rendering data reading unit 28.
The three-dimensional rendering data DB 27 has three-dimensional rendering data, such as data about a polygon or texture, recorded therein. The three-dimensional rendering data is necessary for generating a three-dimensional map, which is a three-dimensional image.
The three-dimensional rendering data reading unit 28 reads the three-dimensional rendering data necessary for generating a three-dimensional map from the three-dimensional rendering data DB 27 on the basis of the rendering object data supplied from the three-dimensional map data retrieving unit 26. In addition, the three-dimensional rendering data reading unit 28 performs rendering on the basis of the three-dimensional rendering data to generate a three-dimensional map, which is a three-dimensional image, and supplies the generated three-dimensional map to the display unit 29. The three-dimensional map is generated with respect to the focal point acquired by the focal point acquiring unit 22 toward the azimuth acquired by the azimuth acquiring unit 23.
The display unit 29 is, for example, a liquid crystal display (LCD). The display unit 29 displays the three-dimensional map supplied from the three-dimensional rendering data reading unit 28.
In the vehicle navigation apparatus 21 having the above configuration, the current position acquired as the focal point by the focal point acquiring unit 22 and the azimuth of the vehicle, acquired by the azimuth acquiring unit 23, are supplied to the rendering area calculating unit 24. The rendering area calculating unit 24 calculates the rendering area on the basis of the focal point supplied from the focal point acquiring unit 22 and the azimuth supplied from the azimuth acquiring unit 23 and supplies the calculated rendering area to the three-dimensional map data retrieving unit 26. The three-dimensional map data retrieving unit 26 retrieves, from the three-dimensional map data DB 25, the rendering object data within the rendering area supplied from the rendering area calculating unit 24 and supplies the retrieved rendering object data to the three-dimensional rendering data reading unit 28. The three-dimensional rendering data reading unit 28 reads the three-dimensional rendering data from the three-dimensional rendering data DB 27 on the basis of the rendering object data supplied from the three-dimensional map data retrieving unit 26 and performs the rendering on the basis of the three-dimensional rendering data to generate a three-dimensional map, which is a three-dimensional image. The three-dimensional rendering data reading unit 28 supplies the generated three-dimensional map to the display unit 29 that displays the three-dimensional map.
FIG. 2 schematically shows three-dimensional map data recorded in the three-dimensional map data DB 25 in FIG. 1.
In the three-dimensional map data DB 25, the three-dimensional map data is divided into, for example, pieces of data in rectangular areas (hereinafter appropriately referred to as “unit areas”) and the pieces of data in the unit areas are stored in files. The rectangular areas are given by segmenting the map in the latitude and longitude directions into an array. The three-dimensional map data includes the rendering object data concerning the rendering objects, such as buildings, located within each unit area.
In the vehicle navigation apparatus 21 shown in FIG. 1, the rendering area calculating unit 24 calculates unit areas included in a range a predetermined distance from a line segment that has a predetermined length and that extends from the focal point acquired by the focal point acquiring unit 22 toward the azimuth acquired by the azimuth acquiring unit 2. The calculated unit areas are set as the rendering area. Referring to FIG. 2, two (latitude direction)×four (longitude direction) unit areas, surrounded by a broken line, are set as the rendering area.
The three-dimensional map data retrieving unit 26 determines two unit areas in the rendering object data concerning the rendering objects in the rendering area to be a neighboring region close to the focal point. The two unit areas, surrounded by a bold line, include a unit area including the focal point and a unit area closest to the unit area including the focal point. The three-dimensional map data retrieving unit 26 retrieves the rendering object data concerning the rendering objects within the unit areas, which is in the neighboring region, from the three-dimensional map data DB 25 and supplies the retrieved rendering object data to the three-dimensional rendering data reading unit 28.
The three-dimensional rendering data reading unit 28 renders the rendering objects on the basis of the rendering object data supplied from the three-dimensional map data retrieving unit 26 to generate a three-dimensional map and supplies the generated three-dimensional map to the display unit 29.
The three-dimensional map displayed in the display unit 29 in the manner described above will now be described with reference to FIGS. 3 and 4.
FIG. 3 schematically shows rendering objects within a rendering area.
Referring to FIG. 3, the rendering objects are located in both the neighboring region close to the focal point and a remote region far from the focal point, in the rendering area.
FIG. 4 schematically shows a three-dimensional map generated for the rendering area shown in FIG. 3.
If all the rendering objects located in the rendering area shown in FIG. 3 are rendered, both the rendering objects in the neighboring region and those in the remote region are displayed in the three-dimensional map, as shown on the left side in FIG. 4.
In contrast, if only the rendering objects located in the neighboring region in the rendering area shown in FIG. 3 are rendered, the rendering objects in the neighboring region are displayed in the three-dimensional map but the rendering objects in the remote region are not displayed therein, as shown on the right side in FIG. 4.